Profiling of the metabolically active community from a production-scale biogas plant by means of high-throughput metatranscriptome sequencing

► First metatranscriptome approach of a biogas-producing microbial community from a production-scale biogas plant. ► Euryarchaeota and Firmicutes are dominant phyla as deduced from taxonomic analysis of metatranscriptome 16S rRNA tags. ► Analysis of metatranscriptome mRNA tags reveals high transcriptional activity of archaeal species. ► Transcripts encoding enzymes involved in biomass hydrolysis, acidogenesis, acetate formation and methanogenesis were identified. ► Transcripts for enzymes functioning in methanogenesis are among the most abundant mRNA tags.